BACKGROUND:Intertrochanteric fracture showed shattered state of different degrees in the clinic. The medial cortex is often a lack of continuity. Indentation and lesser trochanter displacement often cause destruction of biomechanics of femoral calcar to different degrees. Under this condition, it is very important to perform detailed classification of fractures and to strictly master indication of dynamic hip screw. OBJECTIVE:To further analyze the reasons for failure of internal fixation with dynamic hip screw for intertrochanteric fracture. METHODS:Data of 82 patients with intertrochanteric fracture repaired by internal fixation with dynamic hip screw, who were treated at the Department of Orthopedics, Kangtai Branch of the Second Hospital of Lanzhou University from March 2004 to December 2013, were retrospectively analyzed. The reason for failure of internal fixation and prevention method were explored. RESULTS AND CONCLUSION:Al patients were fol owed up for 4-48 months. Time of fracture healing was 12-38 weeks. Fixation failure was found in 12 cases, with an incidence of 15%. Of 12 failure cases, 7 cases affected hip screw cutting out femoral head neck (including 1 case combined with avascular necrosis of the femoral head), 1 case suffered from compression screw slipping out of the tube, 3 cases experienced screw pul ing out and breaking, plate loosening, and 1 case affected steel plate breakage. There were 1 case of Evans II type (8%), 3 cases of type III (25%), 5 cases of type IV (42%), and 3 cases of type V (25%). Lesser trochanter was not completely reset in 5 cases (42%). There were tip-apex distance>25 mm in 7 cases (58%) and early weight loading (3 weeks after fixation) in 1 case (8%). These data confirmed that the selection of indications, the degree of stability after reduction, accuracy of implant position and postoperative unreasonable exercise wil cause fixation failure of dynamic hip screw. Preoperative careful and comprehensive analysis, intraoperative precise operation and postoperative reasonable functional exercise are the keys to ensure success of fixation.

The heart valve prosthesis must have excellent hydrodynamic performance which is usually tested in vitro, not in vivo. This paper comprehensively introduced the principles and methods of hydrodynamic performance in vitro testing, helping clinicians to understand valve performance parameters, evaluate valve applicability, and reduce clinical risk of the valve prosthesis. In vitro testing not only serves as the "gold standard" for valve prosthesis assessment, but also provides detailed data for design and optimization of the prosthesis. ISO 5840 defines the items and methods for valve in vitro testing, which consists of three parts: (1) pulsatile flow testing, which reproduces the pulsating flow of the valve prosthesis after implantation in the human body; (2) steady flow testing, which assesses valve forward flow resistance; (3) durability testing, which evaluates the durability of the valve prosthesis and determines the expected failure   mode. In addition, the paper presented the differences between atrioventricular and aortic valve testing, the method of mitral valve testing, the differences between transcatheter and surgical valve testing, and the method of valve flow visualization.

OBJECTIVE: To investigate the short-term effectiveness of transverse antecubital incision in the treatment of failed closed reduction of Gartland type Ⅲ supracondylar humeral fractures (SHFs) in children. METHODS: Between July 2020 and April 2022, 20 children with Gartland type Ⅲ SHFs who failed in closed reduction were treated with internal and external condylar crossing Kirschner wire fixation through transverse antecubital incision. There were 9 boys and 11 girls with an average age of 3.1 years (range, 1.1-6.0 years). The causes of injuries were fall in 12 cases and fall from height in 8 cases. The time from admission to operation ranged from 7 to 18 hours, with an average of 12.4 hours. The healing of the incision and the occurrence of complications such as nerve injury and cubitus varus were observed after operation; the elbow flexion and extension range of motion after removing the gypsum, after removing the Kirschner wire, and at last follow-up were recorded and compared, as well as the elbow flexion and extension and forearm rotation range of motion at last follow-up between healthy and affected sides; the Baumann angle was measured on the X-ray film, and the fracture healing was observed. At last follow-up, the effectiveness was evaluated according to the Flynn elbow function evaluation criteria. RESULTS: All incisions healed by first intention, and there was no skin necrosis, scar contracture, ulnar nerve injury, and cubitus varus. Postoperative pain occurred in the radial-dorsal thumb in 2 cases. The gypsum was removed and elbow flexion and extension exercises were started at 2-4 weeks (mean, 2.7 weeks) after operation, and the Kirschner wire was removed at 4-5 weeks (mean, 4.3 weeks). All the 20 patients were followed up 6-16 months, with an average of 12.4 months. The fracture healing time was 4-5 weeks, with an average of 4.5 weeks, and there was no complication such as delayed healing and myositis ossificans. The flexion and extension range of motion of the elbow joint gradually improved after operation, and there were significant differences between the time after removing the gypsum, after removing the Kirschner wire, and at last follow-up ( P<0.017). There was no significant difference in the flexion and extension of the elbow joint and the forearm rotation range of motion between the healthy and affected sides at last follow-up ( P>0.05). There was no significant difference in Baumann angle between the time of immediate after operation, after removing the Kirschner wire, and at last follow-up ( P>0.05). According to Flynn elbow function evaluation standard, 16 cases were excellent and 4 cases were good, the excellent and good rate was 100%. CONCLUSION The treatment of Gartland type Ⅲ SHFs in children with failed closed reduction by internal and external condylar crossing Kirschner wire fixation through transverse antecubital incision has the advantages of complete soft tissue hinge behind the fracture for easy reduction and wire fixation, small incision, less complications, fast fracture healing, early functional recovery, reliable reduction and fixation, and can obtain satisfactory results.
Male ; Female ; Humans ; Child ; Child, Preschool ; Calcium Sulfate ; Humerus ; Humeral Fractures/surgery* ; Plastic Surgery Procedures ; Fracture Fixation, Internal/methods* ; Bone Wires ; Fracture Healing ; Treatment Outcome ; Range of Motion, Articular