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Internal Fixation With Absorbable Rods for the Treatment of Displaced Radial Neck Fractures in Children

Su, Yuxi MD, PhD; Xie, Yan MD; Qin, Jiaqiang MD; Wang, Zhongliang MD; Cai, Wenquan MD; Nan, Guoxin MD, PhD

Journal of Pediatric Orthopaedics: December 2016 - Volume 36 - Issue 8 - p 797–802
doi: 10.1097/BPO.0000000000000572

Background: The treatment of radial neck fractures with complete displacement or severe displacement and an angle of >30 degrees is controversial. The currently used methods, including the Metaizeau technique, are associated with drawbacks such as imperfect reduction, epiphyseal damage, and delayed functional recovery. To overcome these drawbacks, we used absorbable rod fixation followed by early functional training for the treatment of displaced radial neck fractures in children.

Methods: In this study, 68 patients (age, 4 to 12 y; average, 8.4 y; average angle, 58 degrees; average displacement, 53%) with radial neck fractures with Salter-Harris grades II to IV underwent lateral elbow open reduction and absorbable rod fixation. At 3 weeks postoperatively, the patients’ plaster casts were removed, and functional training was started.

Results: Anatomic reduction was achieved in all patients. We followed-up 68 patients for 6 months to 4 years (average, 41 mo). No cases of radial nerve injury, radial bone necrosis, myositis ossificans, and postoperative infection were observed. The functional recovery was “excellent” in 43 patients, “good” in 13 patients, “average” in 12 patients, and “bad” in 0 patients, according to the Morrey evaluation standard.

Conclusion: Open reduction with absorbable rod fixation for the treatment of displaced radial neck fractures in children was feasible and was a choice in children.

Level of Evidence: Therapeutic II.

*Department II of Orthopaedics, Stem Cell Biology and Therapy Laboratory, Ministry of Education Key Laboratory of Child Development and Disorders, the Children’s Hospital of Chongqing Medical University

Lab Medicine of Maternity and Child Care Hospital of Yubei District, Lab Medicine of the first affiliated Hospital of Chongqing Medical University, Chongqing, China

Supported in part by research grants from the Natural Science Foundation of China (#81001197 to Y.S., # 81272172 to G.N.); National Key Specialty Construction of Clinical Projects (#2013-544).

The authors declare no conflicts of interest.

Reprints: Guoxin Nan, MD, PhD, Department II of Orthopaedics, Stem Cell Biology and Therapy Laboratory, Ministry of Education Key Laboratory of Child Development and Disorders, the Children’s Hospital of Chongqing Medical University, 136# Zhongshan 2road, Yuzhong District, Chongqing 400014, China. E-mail:

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Radial neck fractures commonly occur in pediatric patients, as epiphysis ossification is incomplete in children.1 These fractures account for 1% of all pediatric fractures and 5% of elbow fractures in children.2 Radial neck fractures with an angle of <30 degrees can be satisfactorily treated with external fixation, especially, in young children. In contrast, the treatment of radial neck fractures with complete displacement or severe displacement and an angle of >30 degrees remains controversial.3 Many authors advocate closed or open reduction4–7 for the treatment of completely or severely displaced radial neck fractures. Closed reduction and fixation with percutaneous Kirschner wires under x-ray guidance has been recommended by Metaizeau et al4 and is widely applied in clinical practice. This treatment is characterized by minimal procedure-related injury and good postoperative functional recovery.5,9 However, Ugutmen et al8 have reported that repeated Kirschner wire reduction by leverage in the Metaizeau technique damages the radial head epiphysis. To overcome this drawback, we used absorbable rods for the fixation of displaced radial neck fractures in children. In this study, we present the outcomes of open reduction, absorbable rod fixation, and early physical rehabilitation in 68 patients with radial neck fractures (Steele-Graham grades II to IV) who were treated at our hospital between January 2008 and June 2011.

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This study involved 68 patients (47 boys and 21 girls) aged 4 to 12 years (average, 8.4 y). All patients had radial neck fractures with an angle of 35 to 105 degrees (average, 58 degrees) and an average displacement of 53%. The fractures were categorized according to the Steele-Graham classification (Table 1).10 Of the 68 patients, 4 had other accompanying fractures (5 with olecranon fractures and 2 medial malleolus fractures). Another 4 patients had elbow dislocation, and 2 patients exhibited radial nerve dysfunction. Most of the injuries were caused by falls, and a few injuries were caused by traffic accidents.

The ethics committee of the Children’s Hospital of Chongqing Medical University approved the study. The parents or guardians of the patients signed an informed consent before participation in the study and as authorization of the publication of the results and use of photographs of their children.

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Absorbable Rods

Absorbable rods were made by ConMed Linvatec Biomaterials Ltd (Tampere, Finland). The rods made of poly-L-lactic acid (SR-PLLA) and of poly-DL-lactic acid plus poly-L-lactic acid composite (SR-PDLLA/PLLA). The molecular mass (Mv) of PLLA was 260.000 and that of PDLLA 100.000. In addition, a special drill, depth scale, and booster were used. The absorbable rods had a diameter of 2.0 mm and length of 5.0 cm.

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Surgical Technique

All of the patients were performed the close reduction. We did the open reduction when the close reduction was failed. A pneumatic tourniquet was used during the surgery to minimize blood loss. Under general anesthesia or basal and brachial plexus anesthesia, an incision was made in the lateral part of the elbow joint and the lateral articular capsule to expose the radial head (Fig. 1) and drain the hematocele. The deep branches of the radial nerve were preserved during the operation. The radial neck periosteum was kept intact, and the angled radial neck was pushed with an orthopaedic elevator or fingers until the humeroradial articular surfaces were as perfectly aligned as possible and reduction was achieved. The periosteum was not dissected during the operation. The fractures were temporarily fixed with a Kirschner wire (diameter, 1.0 mm) inserted near the fracture edges (Fig. 2) after satisfactory reduction was obtained. Then, the center of the articular face of the radial head was drilled (drill bit diameter, 2.0 mm) along the radial axis (Fig. 3), and an absorbable rod (length, 5 cm; diameter, 2.0 mm) was inserted using a booster into the space created, until the end of the rod was parallel with the articular surface. Then, the Kirschner wire used for temporary fixation was removed (Fig. 4). The articular capsule, subcutaneous tissues, and skin were closed in layers after the reduction was confirmed to be satisfactory on a C-arm system and the fixation was confirmed to be reliable by moving the elbow joint. Then, the elbow joint was immobilized in the functional position with a plaster cast. The plaster support was removed after 3 weeks, and functional training was started under the guidance of the doctors. At 6 months after the operation, elbow function was assessed using the Morrey11 evaluation standard. The Morrey evaluation system score was assessed range of motion of the elbow. It includes ulnohumeral motion and forearm rotation, higher scores reflecting better results.

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In this study, 68 patients were followed-up for 6 months to 4 years (average, 3 y and 5 mo). No cases of fracture nonunion or secondary displacement after anatomic reduction were observed. The healing time was 3 to 6 weeks. No radial nerve injuries, radial bone necrosis, myositis ossificans, or postoperative infection occurred. In 2 patients, the fractures were complicated with radial nerve dysfunction. In these patients, hematocele and its forward expansion into the elbow joint, radial nerve congestion, and edema were found intraoperatively. Nerve function was restored spontaneously within 3 to 4 weeks after the operation, and elbow function was restored after 2 months. At 6 months postoperatively, recovery was excellent in all patients, except for 2 patients with poor pronation and 1 patient with poor supination. The functional outcomes were rated “excellent” in 43 patients, “good” in 13 patients, “ordinary” in 2 patients, and “bad” in 0 patients, according to the Morrey evaluation standard (Tables 2 and 3). No abnormal radial head growth was observed during the 4-year follow-up of 28 patients. The x-ray images of typical cases are shown in Figures 5 to 7.

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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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radial neck; absorbable rod; fractures; internal fixation

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