0.1 ?mol?L-1), inducing differentiation through enhancement of melanogenesis and increase of the activity of tyrosinase at lower doses(

Objective:To evaluate collared and bipolar hemiarthroplasty combined with medial femoral calcar reconstruction in the treatment of senile patients with osteoporotic unstable intertrochanteric fracture.Methods:The data of 28 senile patients with unstable femoral intertrochanteric fracture were retrospectively analyzed who had been admitted to Department of Orthopedics, The First Affiliated Hospital to Zhejiang University of Chinese Medicine from March 2014 to February 2020. They were 8 males and 20 females, aged from 75 to 99 years (average, 81.5 years). All the fractures were low violence injuries due to falls. By the Evans-Jensen classification, there were 2 cases of type Ⅲ, 5 cases of type Ⅳ and 21 cases of type Ⅴ. All patients were osteoporotic, with a BMD T-score ranging from -4.5 to -2.0. Surgery was performed 2 to 6 days after injury (3.8 days on average). Corail collared femoral stems and bipolar ball heads produced by DePuy company were selected for implantation during surgery. Their fractures were reduced and fixated by titanium wire bundling system or bifilar winding wire bundles. The femoral calcar reconstruction was accomplished by inserting the beak-shaped distal part of the head-neck fracture fragment into the femoral medullary cavity together with the medial side of the stem just under the collar and impacting it to a tight position.Results:The average operation time for this group of patients was 62 min (from 50 to 85 min) and the average intraoperative blood loss 170 mL (from 110 to 320 mL). All the 28 patients were followed up for 10 to 71 months (average, 46 months). Their Harris hip scores averaged 92 points (from 89 to 96 points) at 6 months after operation. Two patients developed intermuscular venous thrombosis in the calf after operation. During follow-up, none of the patients had such complications as deep iliac femoral vein thrombosis, pulmonary embolism, incision infection, or deep prosthesis infection. At the last follow-up, their Harris hip scores averaged 88 points (from 82 to 96 points).Conclusion:For some senile patients with osteoporotic unstable intertrochanteric fracture, collared and bipolar hemiarthroplasty combined with medial femoral calcar reconstruction can achieve fine therapeutic efficacy.

Objective:To investigate the biomechanical properties of a self-developed crossed-hug locking plate system in fixation of Vancouver type B1 periprosthetic femur fractures.Methods:Vancouver type B1 periprosthetic femur fractures in clinic were simulated in 3 samples of artificial adult femur produced by Sawbone corporation in USA, including 2 of model 3403 and 1 of model 3447. The fractures were then fixed with our self-developed crossed-hug locking plate system. After the load state of the human body in the upright stance was simulated on an experimental machine, compression tests (with a loading force of 50 to 500 N, and a displacement controlled acceleration of 5 mm/min), compression fatigue tests (with a loading condition of 50 to 500 N sine wave force value, a frequency of 5 Hz, and cyclic loading of 250 times), torsion tests (torque loaded at an torque angle acceleration of 1°/min to 15°/min in clockwise rotation), and torsion failure tests were conducted in sequence.Results:The axial compression tests showed that the displacements in the 3 samples were 0.83 mm, 0.45 mm and 0.41 mm, respectively, leading to no abnormal changes in the crossed-hug locking plate system in all samples. The compressive fatigue tests showed that the displacements in the 3 samples were (0.70±0.05) mm, (0.44±0.01) mm, and (0.42±0.02) mm, respectively, with the maximum displacement change less than 0.13 mm, leading to no abnormal changes in the crossed-hug locking plate system in all samples. The torsion within 4° in the torsion test showed that the maximum torque was 4.73 N·m in sample 1, 7.82 N·m in sample 2, and 7.37 N·m in sample 3. In the torsion failure tests, sample 1 was fractured at the first screw in the distal femoral bone plate, with an ultimate torque of 28.18 N·m. In sample 2, the torque at which the hook started to slide was 16.00 N·m, and the ultimate torque at which the hook broke to cause internal fixation failure was 18.74 N·m. The torque at which the hook started to slide in sample 3 was 20.49 N·m, and the ultimate torque at which the hook broke to cause internal fixation failure was 24.82 N·m.Conclusion:Our self-developed crossed-hug locking plate for Vancouver type B1 periprosthetic femur fractures has achieved the mechanical strengths required in the mechanical tests which simulate human upright load with Sawbone biomechanical test materials.