Finite Element Analysis on Different Internal Fixations for Treating Proximal Humeral Fractures in Children / 医用生物力学

Objective To compare biomechanical characteristics of external fixator, Kirschner’s wire, elastic stable intramedullary nailing (ESIN) for fixing proximal humeral fractures in children by finite element method.Methods The CT scanning data from the healthy humerus of an 8-year-old patient with proximal humeralfractures were collected, and the image data were imported in Mimics 21. 0 to establish the rough humeralmodel, which was imported in Geomagic 2013 to construct the three-dimensional (3D) model of cancellous and cortical bones of the humerus. After the model was assembled with 3 fixators ( external fixator, Kirschner’swire, ESIN), it was imported in ANSYS 2019 to simulate the upper limb under quiet, abduction, adduction, flexion, extension, external rotation, internal rotation working conditions. The maximum displacement of the distal humerus, the maximum stress of the fixture, and the maximum displacement of the distal fracture surface were analyzed. Results The minimum values of the maximum displacement of the distal humerus in models fixed by external fixator, Kirschner’s wire, ESIN appeared under extension (2. 406 mm), external rotation (0. 203 mm), external rotation (0. 185 mm) working conditions, respectively. Conclusions External fixator is the most unstable fixation of proximal humeral fractures in children, and the biomechanical performance of ESIN is better than that of external fixator and Kirschner’s wire fixation

Diagnosis and treatment of a head-neck separation type of Monteggia equivalent fractures in children / 中华创伤骨科杂志

Objective:To explore the clinical characteristics and treatment of a head-neck separation type of Monteggia equivalent fractures in children.Methods:From March 2016 to February 2019, 12 children sought medical attention at Pediatric Orthopedic Hospital, Honghui Hospital Affiliated to Xi'an Jiaotong University for a head-neck separation type of Monteggia equivalent fractures. They were 8 boys and 4 girls, aged from 3 to 14 years (average, 8.3 years). All cases were treated with closed reduction, deformity correction and plaster fixation at emergency department after X-ray examination. In line with the treatment principles for Monteggia fractures, after the ulnar length was first restored and stabilized, a proper fixation method was chosen according to the location and type of the ulnar fracture, followed by treatment of the radial neck fracture. The fracture union and complications were evaluated according to the X-ray films after operation, and the therapeutic efficacy was evaluated according to the Mayo elbow performance score (MEPS) at the final follow-up.Results:The head-neck separation type of Monteggia equivalent fractures in children was characterized by a fracture of ulnar diaphysis or metaphysis and a fracture of the radial neck with complete separation of the head and neck, a longitudinal axis of the radius off the capitellum center at the distal fracture end but normal proximal humeroradial relationship. The fractures were classified into 2 types depending on the angulation direction of the ulnar fracture and the direction of distal displacement of the radial neck fracture: 7 cases belonged to the extension-valgus type and 5 cases to the flexion-varus type. The 12 patients were followed up for 8 to 38 months (average, 16.0 months). Of the ulnar fractures, one was treated with closed reduction and Kirschner wire fixation, 4 with elastic intramedullary nail fixation, 5 with plate fixation, one untreated, and one with manual reduction only. Of the radial neck fractures, 11 were treated with closed reduction and elastic intramedullary nail fixation, and one with open reduction and K-wires fixation. All fractures got united after 8 to 12 weeks (mean, 9.6 weeks). The time for removal of internal fixation ranged from 12 to 50 weeks (mean, 31.2 weeks). Avascular necrosis occurred in one case and bulk formation of proximal metaphysis in another. By the MEPS at the final follow-up, the therapeutic efficacy was excellent in 10 cases, good in one and fair in one.Conclusions:The head-neck separation type of Monteggia equivalent fractures in children is different from common Monteggia fractures or radial neck fractures, because its clinical manifestations are characterized by a fracture of ulnar diaphysis or metaphysis and a fracture of the radial neck with complete separation of the head and neck, a longitudinal axis of the radius off the capitellum center at the distal fracture end but normal proximal humeroradial relationship. The treatment options for ulnar fractures include closed reduction with Kirschner wire fixation, elastic intramedullary nailing, open reduction and bone plate fixation or no fixation, while radial neck fractures are mostly treated by closed reduction and elastic intramedullary nailing. Early functional exercise can lead to satisfactory clinical outcomes.

Clinical characteristics and treatment of complex fracture-dislocations of the elbow in children / 中华骨科杂志

Objective:To summarize and discuss the concept and clinical manifestations of complex fracture-dislocations of the elbow in children, and compare its injury characteristics, treatment and clinical effect with adults.Methods:From September 2015 to January 2020, 34 patients seen and treated at our institution for complex fracture-dislocations of the elbow were identified, and their medical records and radiographs were reviewed retrospectively. The inclusion criteria were elbow dislocation combined with one or more fractures at the proximal ulna and radius. There were 25 boys and 9 girls, with an average age of 8.3±3.2 years. The left arm was involved in 27 cases, and the right arm was involved in 7 cases. The causes of injury included falling from a scooter in 16 cases, falling from height in 10 cases, cycling in 5 cases and traffic accident in 3 cases. All patients were treated with closed reduction and the application of plaster under local anaesthesia in the emergency room. Then, X-ray, CT and MRI were performed to evaluate the fracture-dislocation and ligament injury. The following treatment plan was comprehensively evaluated according to the size and displacement of the combined fracture block and the stability of the elbow, for example, open reduction with K-wires and tension band or plate fixation for olecranon fracture, open reduction with loop plate fixation for coronal process fracture, closed reduction or open reduction with K-wires or elasticstable intramedullary nail for radial neck fracture.Results:Among the 34 patients, there were 16 cases of transolecranon fracture-dislocation, 1 case of varus posteromedial rotational instability, 4 cases of valgus posterolateral rotatory instability and 13 cases of divergent dislocation of elbow. All patients were followed up for 13(8, 15) months, and the average fracture healing time was 3.5±0.8 weeks, with no failure of internal fixation. In 2 cases of elbow dislocation combined radial neck fracture, one case had ischemic necrosis of the radial head and one case had early closure of epiphyseal plate of the proximal radius. At the last follow-up, all patients had no subluxation, dislocation or instability of the elbow. The therapeutic efficacy was evaluated at the final follow-up by the Mayo elbow performance score (MEPS) as excellent in 25 cases, good in 5 cases, fair in 3 cases, and poor in one case, with excellent and good rate 88%.Conclusion:The complex fracture-dislocations of the elbow is rare in children. We have the opinion that the clinical characteristics are dislocation combined with one or more fractures of the proximal ulna and radius. Compared with adults, its pathological characteristics and the scope of injury are similar, but most of the injuries are mild. The clinical manifestations are mainly transolecranon fracture-dislocation and divergent dislocation of elbow. Good results can be achieved in most cases through open reduction with internal fixation for fractures.

Intramedullary plus extramedullary fixation for fracture of distal radial diametaphyseal transition zone in children / 中华创伤骨科杂志

Objective:To investigate the efficacy of intramedullary plus extramedullary fixation in the treatment of fractures of distal radial diametaphyseal transition zone in children.Methods:The data were retrospectively analyzed of the 49 children who had been admitted to Pediatric Orthopedic Hospital, Honghui Hospital Affiliated to Xi'an Jiaotong University from July 2018 to April 2020 for fractures of distal radial diametaphyseal transition zone. There were 30 males and 19 females; 21 left sides, 27 right sides, and one case of bilateral sides. In the operation, an elastic intramedullary nail or Kirschner wire was used for intramedullary fixation while another Kirschner wire was used to fix the cortex at the distal and proximal ends of the fracture. The ranges of wrist motion and Disabilities of the Arm, Shoulder and Hand (DASH) scores at 1 and 9 months after operation were recorded and compared; the incidence of postoperative complications was also recorded.Results:The operation time for the 49 children averaged 45.0 min (from 39 to 51 min). The patients were followed up for 6 to 36 months (mean, 18.6 months). The fracture union time averaged 8.6 weeks (from 6.8 to 10.4 weeks). Needle tract infection developed in one case but the wound was healed after removal of the K-wire after callus formation and oral use of antibiotics for 3 days. Another case reported skin irritation the symptoms of which disappeared after the child reduced activities. The ranges of pronation, supination, flexion and extension of the wrist and DASH score were 47.9°±2.5°, 45.5°±3.0°, 51.2°±1.6°, 53.4°±1.7° and (36.7±4.5) points at one month after operation while they were 85.6°±3.1°, 87.6°±2.1°, 88.8°±2.0°, 88.0°±1.2° and (23.2±8.6) points at 9 months after operation. There were statistically significant differences in the above indexes between one and 9 months after operation ( P<0.05). Conclusion:In the treatment of fractures of distal radial diametaphyseal transition zone in children, intramedullary plus extramedullary fixation is simple in surgical techniques, easily repeatable, slightly invasive, and reliable in fixation.

Treatment of nonunion of lateral humeral condyle complicated with cubitus valgus with primary fixation in situ and secondary supracondylar varus osteotomy / 中华创伤骨科杂志

Objective:To evaluate the treatment of nonunion of lateral humeral condyle complicated with cubitus valgus with primary fixation in situ and secondary supracondylar varus osteotomy.Methods:A retrospective analysis was made of the 8 children who had been treated for nonunion of lateral humeral condyle complicated with cubitus valgus at Department of Pediatric Orthopedics, Honghui Hospital from January 2016 to March 2018. They were 5 boys and 3 girls with 5 left and 3 right sides involved. Their age at injury ranged from 6 to 14 years (average, 10 years) and the duration from injury to operation from 2 to 6 years (average, 4 years). At the primary stage, the fragments were fixated in situ with compressive cannulated screws after cleaning the nonunion ends, followed by iliac autograft. At the secondary stage, the humeral supracondylar varus osteotomy was performed after the nonunion was healed and the elbow range of motion recovered. The therapeutic effects were assessed by comparing the elbow range of motion, carrying angle and Mayo elbow performance score (MEPS) between preoperation and the final follow-up.Results:All the patients were followed up for an average of 44.5 months (range, from 27 to 64 months). The average healing time for obsolete nonunion of lateral humeral condyle was 81.3 days (range, from 55 to 120 days) after the primary operation and that for supracondylar varus osteotomy 51.1 days (range, from 45 to 60 days) after the secondary operation. The elbow range of motion was 129.0°±4.6° before operation and 138.0°±5.4° at the final follow-up, showing a significant difference ( P<0.001). The average carrying angle at the healthy side in 8 children was 5.4° (range, from 3° to 8°). The carrying angle at the affected side was 31.9°±4.7° (range, from 25° to 42°) before operation and 4.0°±2.2°(range, from 1° to 8°) at the final follow-up, showing a significant difference ( P<0.05). Their preoperative MEPS was 57.5 ± 6.5 (4 good cases and 4 poor ones) but 95.9±3.4 (6 excellent cases and 2 good ones) at the final follow-up, showing a significant difference ( P<0.05). Conclusions:Treatment of nonunion of lateral humeral condyle complicated with cubitus valgus can be effectively carried out by cleaning fibrous tissue in the nonunion gap, iliac autograft and fragments fixation in situ with compressive cannulated screws at the primary stage and supracondylar varus osteotomy at the secondary stage. Intraoperative preservation of the blood supply to the nonunited fragments is the key to successful management.

The effect of NovaBone combined with autologous iliac in the acetabular osteotomy of children with developmental dislocation of the hip / 中华骨科杂志

Objective To compare the effect of application of autologous iliac alone and NovaBone combined with autologous iliac in the acetabular osteotomy of children with developmental dislocation of the hip (DDH).Methods Data of 113 cases of children with DDH who had undergone open reduction and acetabular osteotomy surgery from 2007 to 2011 were retrospectively analyzed.According to bone material using after acetabular osteotomy,the patients were divided into autogenous iliac bone graft group (52 cases,60 hips) and NovaBone combined with autologous iliac bone graft group (61 cases,67 hips).There were no statistical differences in gender,age,side,dislocation type,osteotomy and acetabular index between the two groups.The patients were evaluated by Lane's scoring criteria,Severin standards and McKay standards at 6 weeks,3 months,6 months,1-year and 2-year post-operation follow-up.The bone healing of acetabular osteotomy zone,radiography and function of hip were compared.Results 6 weeks and 3 months after operation,Lane bone healing score in NovaBone combined with autologous iliac bone graft group (6.4±1.3 points and 9.6±1.7 points respectively) was obviously superior to autogenous iliac bone graft group (4.7±1.5 points and 7.8±1.2 points respectively).And 6 months and 1 year after operation,the two groups were basically reached bone healing.The Severin standard results showed that the rate (94％,63/67) of Excellent and Good in NovaBone combined with autologous iliac bone graft group (excellent:41 hips,good:22 hips,Fair:4 hips) was significantly higher than the rate (83.3％,50/60) in autogenous iliac bone graft group (excellent:28 hips,good:22 hips,Fair:10 hips).The rate (16.7％,10/60) of Fair in autogenous iliac bone graft group was significantly higher than the rate (6.0％,4/67) in NovaBone combined with autologous iliac bone graft group.McKay standard results were consistent with the results of radiological evaluation.Conclusion As a novel bone defect repair material,NovaBone can promote early bone healing process of acetabular osteotomy areas.It also can improve the resistance of osteotomy area.NovaBone can get a satisfied result in acetabular osteotomy in children with DDH.