Radial neck fractures are common in children aged 8 to 11 years. Generally, external plaster fixation is used to treat radial neck fractures when the angle is <30 degrees. Closed reduction1 under anesthesia is recommended when the angle is >30 degrees. Factors causing poor union of pediatric radial neck fractures include relatively older age, severe displacement, delay in treatment, unsatisfactory reduction, and open reduction.4,6 The application of open versus closed reduction for the treatment of severely displaced and angulated radial neck fractures remains controversial.3,5,7,8,10 This is also the key question that we cared most when the surgery were firstly performed. When we did the surgery, we found the bone cortex of the neck of radius was partly intact, and the periosteum were also intact. Both factors gave the strength of fixation together with polylactide absorbable rods. Most authors recommend the use of surgical methods for the treatment of severely displaced and angulated fractures.5,7–9
With further studies of the functional anatomy of the elbow joint, the preservation of elbow joint integrity in patients with radial neck fractures is increasingly stressed on in clinical practice. Restoration of the original anatomic shape of the radial neck and joint surfaces to the greatest possible extent is especially important in pediatric patients. The forearm is mainly used for rotation, which is jointly achieved by the proximal radioulnar joint and the distal radioulnar joint. Anatomic reduction of radial neck fractures must be achieved to restore this function. Accurate reduction of radial neck fractures cannot be achieved by manipulative reduction and percutaneous pin fixation in all patients. Therefore, we consider that open reduction, internal fixation, and early functional training are indicated in radial neck fracture patients with a >30-degree angle of inclination, >2 mm displacement, or failure of closed reduction, to restore elbow joint function to the greatest possible extent.
Generally, Kirschner wires are used for internal fixation. Functional training cannot be commenced before the removal of the Kirschner wires, as their ends protrude out of the skin after fixation. Thus, functional recovery is delayed after fixation with Kirschner wires. In addition, children, especially young children, tend to be afraid of pins. Furthermore, the Kirschner wire needs to be removed by a second operation, which increases the physical and psychological trauma to the children. Moreover, in some cases, the Kirschner wire can break. To overcome these drawbacks, we used an absorbable SR-PLLA rod for the internal fixation of radial neck fractures.
SR-PLLA is an absorbable polymer.11 Animal studies have shown that SR-PLLA has no toxic reactions and has good histocompatibility.12,13 Furthermore, mechanical tests have shown that the maximum shearing strength of bolts made from SR-PLLA is equal to that of steel bolts and titanium bolts, and their compressive strength is equal to that of steel bolts and significantly higher than that of titanium bolts.14 The SR-PLLA rod expands vertically and shrinks horizontally after being immersed in water under automatic compression,15 these properties help increase the strength of fixation. Generally, it loses its mechanical strength within 3 to 12 months and is completely absorbed within 2 to 4 years.16 Therefore, the absorbable rod would not lose its mechanical strength before fracture union. The absorbable rod not only facilitated good fracture fixation but also maintained the normal stress stimulate the fracture site, thereby avoiding stress-shielding effects. In addition, it had sufficient biological strength and a modulus of elasticity close to that of human bone.15 No cases of nonunion and secondary fracture displacement were observed in our study. We believe that early functional training can reduce peripheral tissue adhesion and promote functional recovery.
Metaizeau4 argued that intra-articular ossification, ischemic necrosis of the radial head, and ankylosis were common after the open reduction of radial neck fractures. In our study, the local blood circulation at the fracture site was not affected, as the periosteum was not dissected during the surgery. Fracture reduction was achieved by the correction of the articular surface angle. Perfect apposition of the humeroradial joint implies successful reduction and correction of axial displacement only if the periosteum, which is relatively thick in this area, is kept intact after the fracture. No radial head necrosis, or cubitus or valgus deformities were observed during follow-up in our patients, which indicated that the growth of the radial head was not affected in the short term and that epiphyseal damage was minimized with our method. However, long-term follow-up is necessary as the radial head epiphysis in most of our patients had not completely closed. Good functional recovery in our patients was related to the early functional training.
Although good outcomes were achieved after the reduction of radial neck fractures with absorbable rods, we must emphasize that open reduction and internal fixation with absorbable rods is only indicated in patients with Steele-Graham grades of II or more and failure of manipulative reduction. Elastic steel wire reduction and fixation have been used by many authors in recent years, with satisfactory results.4,8 Open reduction is unnecessary if the above method is applied, which complies with the concept of minimally invasive surgery. In our study, we did not see the avascular necrosis in follow-up of these patients. We predicted that there maybe 2 reasons for this. First, we try our best to minimize the damage during the surgery especially for the intact of the periosteum. Second, may be the limited number of patients in this study and our observation was not long enough. They may be seen after long observation. A limitation of our method is that imaging with a C-arm system is required during the operation, which increases the radiation exposure in both doctors and patients.
In conclusion, the combination of open reduction, absorbable rod fixation, and early functional training is indicated for the treatment of pediatric radial neck fractures with obvious displacement that are unsuitable for closed reduction. Our procedure is characterized by a simple operation, good fracture union, few sequelae, good functional recovery, lack of reoperation, and decreased psychological trauma to the children.
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Keywords:Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
radial neck; absorbable rod; fractures; internal fixation