Pre‐bent elastic stable intramedullary nail fixation for distal radial shaft fractures in children

Abstract

Objective:  To investigate the functional and radiographic outcomes of pre‐bent elastic stable intramedullary nail in treatment of distal radial shaft fractures in children.

Methods:  From January 2006 to December 2008, 18 children with distal radial shaft fracture were treated by close reduction and internal fixation with a pre‐bent elastic stable intramedullary nail. The age range was from 5 years to 15 years, with an average of 9 years and 8 months. The minimum follow‐up was 12 months.

Results:  All fractures maintained good alignment postoperatively, and 94.4% (17/18) of the patients regained a full range of rotation of the forearm. One patient has limitation of rotation to less than 10°, this had improved by final follow‐up. Complications included soft tissue irritation at the site of nail insertion in one patient and transient scar hypersensitivity in another.

Conclusion:  Fixation with a pre‐bent elastic stable intramedullary nail is an effective, safe and convenient method for treating distal radial shaft fractures in children.

Introduction

Fracture of the radial shaft is a common fracture in children. Incomplete or minimally displaced fractures heal readily with standard closed treatments. Completely displaced fractures of the radial shaft have also traditionally been treated by closed methods. With the encouraging results of elastic stable intramedullary nailing (ESIN) for treatment of femoral shaft fractures in children, this technique has been extended to the management of forearm fractures. So far, both short and long‐term results of the treatment of forearm fracture with ESIN are satisfactory, with a low incidence of complications. In the experience of the present authors, it is very difficult to maintain the alignment of the distal radial shaft fracture by the classic technique of the ESIN. In this study, the method of pre‐bent ESIN to keep the nail straight at the fracture site was adopted, and good alignment of the fracture after close reduction was maintained by this method. The intention of this study was to review the clinical and radiographic results of fixation with pre‐bent ESIN for distal radial shaft fractures in children.

Materials and methods

All patients who had undergone operative treatment for distal radial shaft fractures in our department from January 2006 to December 2008 were retrieved from the database. Inclusion criteria for the cases were: (i) age ≤ 16 years; (ii) closed and completely displaced distal radial shaft fractures; (iii) fixation by ESIN; and iv) intraoperative application of the pre‐bending technique to maintain the alignment of the fracture. Exclusion criteria for patients were: (i) age > 16 years; (ii) treatment by open reduction and internal fixation; and (iii) a diagnosis of pathological fracture. The minimum follow‐up time for all patients was 1 year.

Follow‐up information included: (i) the patient's age at the time of surgery; ii) the time interval between injury and surgery; (iii) any complications arising from treatment; (iv) radiological information, including the degree of fracture angulation and alignment, diameter of the intramedullary nail, postoperative fracture alignment, and final fracture healing time (taken as the time of nail removal); (v) the children's forearm rotatory function; and (vi) the parents’ satisfaction with the treatment.

Surgical technique

All operations were performed under general anesthesia with the patient in a supine position. The diameter of the ESIN was determined as 2/3 of the narrowest part of the radial canal. C‐arm fluoroscopy was applied to determine the fracture site and distal radial metaphysis. As in the classical method, the entry point of the ESIN was located in the dorsal radial metaphysis. The nail was attached to a T‐handle and introduced into the entry hole. Then, under C‐arm fluoroscopy guidance, the nail was introduced proximally using gentle rotational movements of the T‐handle until it reached the fracture site. Fracture reduction was performed under C‐arm fluoroscopy, and then the nail advanced to the proximal segment of the fracture.

Because the fracture site was very near the entry point and the ESIN was flexible, the fracture would still have some angulation deformity and malalignment. Accordingly, the nail was pre‐bent outside the skin incision to about 30°, and then the corner part of the intramedullary nail was advanced into the medullary cavity. Removing the flexibility of the intramedullary nail made it relatively straight at the fracture site, and thus good position and alignment of the fracture could be maintained. Using C‐arm fluoroscopy permitted confirmation of good position and alignment of the fracture. The tail of the nail was buried in the subcutaneous tissue. All patients were placed in an above elbow plaster cast postoperatively.

A typical case of a 9‐year‐old male patient with distal radial and ulnar fractures on the right treated by the method described above is illustrated in Figures 1a–c. The time interval between injury and surgery was 1 day.

Figure 1.

A 9‐year‐old boy with a sport‐related fracture of the right distal part of the radial and ulnar shafts. (a) X‐films of the initial injury show complete displacement of the right distal radius and ulnar fracture. (b) Postoperative X‐films show the radial fracture has been reduced and fixed with a pre‐bent ESIN. The alignment of the fracture is good. (c) Six months postoperatively, X‐films show the fracture has healed and remodeled completely.

Results

General data

There were 18 patients altogether, including 13 boys and 5 girls. The average age was 9 years and 8 months (5–15 years). Twelve cases were in the left radius, and six in the right. All were closed fractures, and the time intervals from injury to surgery were 1–9 days. The fracture sites were all located in the distal radial shaft; 15 cases had ipsilateral ulnar fractures and the other three had solitary radial fractures. Closed reductions were performed under C‐arm fluoroscopy. All affected arms were immobilized in the functional position postoperatively with a plaster cast beyond the elbow. Time to complete healing of the fracture was defined as the time interval between the initial operation and removal of the nail. The average time for complete fracture union was 5 months (3–7 months).

Therapeutic outcomes

The average preoperative alignment of the fractures was 52.2% ± 28.9% on the anteroposterior view and 22.9% ± 34.0% on the lateral view. The average preoperative angulation of the fractures was 16.2°± 7.5° on the anteroposterior view and 26.2°± 13.1° on the lateral view. The average postoperative alignment of the fractures was 93.2% ± 5.9% on the anteroposterior view and 95.7% ± 7.1% on the lateral view. The average postoperative angulation of the fractures was 2.7°± 1.5° on the anteroposterior view and 1.4°± 1.2° on the lateral view. The mean follow‐up time was 15 months (range, 12–19 months). One patient had limited forearm rotation which was less than 10° in the early period after removal of cast, the range of movement having improved significantly by the final follow‐up. Seventeen patients (94%) regained full forearm rotation.

Complications

One patient had transient scar hypersensitivity which disappeared 4 months postoperatively. Skin irritation caused by the nail end occurred in another one, and that resolved after removing the internal fixation. When asked, 100% of the parents expressed their satisfaction with the treatment.

Discussion

Overview

Generally speaking, most forearm fractures in children can be treated conservatively because of the potential for remodeling. However, the outcome of treatment may be disappointing in older children. It is now well accepted that forearm fractures with angulation of more than 10° after reduction, or completely displaced fractures, require operative intervention ¹ , ² . In the past, many doctors have chosen a plate or Kirschner wire for internal fixation. Generally, a plate is considered to be reliable, but there are some problems such as major surgical trauma, nonunion, and the need for a second operation to remove the fixation. Intramedullary fixation with a Kirschner wire involves fewer invasions and is easy to remove, but epiphyseal injury is a potential problem.

ESIN for diaphyseal fractures in children

In the past 25 years, the ESIN method has become a widely accepted, standard surgical procedure for diaphyseal fractures in children and adolescent. The advantages of ESIN are that the entry point is located at the metaphysis, thus avoiding epiphyseal plate injury and it is minimally invasive surgery, facilitating postoperative recovery. Intramedullary multi‐point fixation allows maintenance of the fracture line of force at the same time, producing vertical micro‐movement at the fracture site, which helps callus formation, so the technology is very suitable for long bone fracture in children. With the elastic intramedullary nailing technique having become more and more popular, more surgeons now accept the ESIN method for treating children's forearm fractures ¹ , ³ , ⁴ . Short and long term follow‐up of ESIN for pediatric forearm fractures has shown good outcomes ⁵ , ⁶ , ⁷ .

Previous experience of ESIN for distal radial shaft fracture

The initial experience was that ESIN fixation was not suitable for distal radial shaft fracture ⁸ . The reasons are as follows: (i) the entry‐point is too close to the fracture site, (ii) fracture alignment cannot be maintained, and (iii) the anti‐rotation force is weak. Meanwhile, from an anatomical point of view, there is 9^o physiological curvature to the radial side in the distal radial shaft. The classical elastic intramedullary nail minimally invasive technique (entry point at the dorsal lateral distal radial metaphysis) has met with some problems; namely, once the intramedullary nail is across the fracture site, it tends to push the proximal side of the fracture to the ulnar side because of the nail's flexibility. This causes poor alignment of the fracture, and an inability to maintain the physiological curvature of the distal radius and sustain the interosseous membrane tension. Interosseous membrane tension is very important for the function of forearm rotation ⁹ , ¹⁰ . For these reasons, some scholars have reported a number of alternative methods, for example, locating the intramedullary nail entry point in the middle of the radius ¹¹ , ¹² , so that when the intramedullary nail passes through the fracture site, it can be kept relatively straight, thus allowing maintenance of fracture alignment and interosseous membrane tension. This approach has achieved good results, but it also has some shortcomings, including potential injury to the deep branch of the radial nerve, as well as the need to put an entry hole in the radial diaphysis, making the operation relatively more difficult.

Experience of ESIN for distal radial shaft fractures

In the experience of the present authors, it is unnecessary to change the classical approach when using an elastic intramedullary nail to treat fracture of the distal part of the radial shaft; the entry point can still be at the distal radial dorsal metaphysis. When the ESIN had been advanced into the proximal part of the radius, the nail is pre‐bent about 30° near its entry point, and then the corner part of the intramedullary nail is advanced into the medullary cavity. When the intramedullary nail passes through the fracture side, it can be kept relatively straight, thus maintaining fracture alignment and interosseous membrane tension. This is very helpful for functional recovery of forearm rotation postoperatively. This approach had the following advantages: (i) it expands the indications for ESIN; (ii) it retains the inherent advantages of ESIN such as minimal invasion, intramedullary multi‐point fixation and vertical micro‐movement; (iii) taking into account the characteristics of fracture of the distal part of the radial shaft, it removes the flexibility of the nail, allowing good fracture alignment and maintenance of the physiological distal radius curvature and interosseous membrane tension. In this study, the follow‐up results of all patients were satisfactory; (iv) because it is unnecessary to change the nail's entry point to the proximal radial shaft, it does not have the risk of potential nerve injury; and (v) the surgical technique is relatively easy to learn.

Postoperative cast immobilization is currently controversial, some scholars having advocated surgery without cast immobilization and early functional rehabilitation exercises. Long arm cast immobilization was used on all patients in this group for 3–4 weeks postoperatively, after which an X‐ray film was taken. The cast was removed once the X‐ray showed some callus formation. We believe that a single pre‐bent nail may not achieve rigid fixation. Without cast immobilization, it is difficult to ensure that a certain degree of re‐displacement at the fracture side does not happen. In children, the functional limitations after plaster removal can often be improved in a relatively short time through functional exercise. Therefore, we used postoperative cast immobilization.

In summary, we believe that pre‐bent ESIN is suitable for distal radial shaft fractures, this method is effective, safe, easy to learn, and is an option for distal radial shaft fracture in children.

Disclosure

None of the authors received any financial support for this study.