2.1 The Amsterdam Pediatric wrist rules

The management of a child with acute wrist injury starts with history taking, physical examination, and conventional X-ray evaluation. The child or his/her parents usually describe a low-energy fall with the hand outstretched for protection. The swelling, local tenderness, wrist deformity, and motion restriction are usually found on physical examination. The emergency physician or orthopedic surgeon usually orders X-ray imaging at this step to confirm the diagnosis. Recently, the Amsterdam Pediatric Wrist Rules have been developed and validated for the use of X-ray in children with acute wrist injury. It has the sensitivity and negative predictive value of 98 and 95 %,respectively.³ The guideline combines patient's demographic data with clinical findings including wrist swelling, deformity, tenderness, and motion restriction to select patients with acute wrist injury for radiographic evaluation. The implementation of the guideline has resulted in 15.3 % wrist radiographies reduction.⁴

Unlike the Ottawa ankle rule which is usually implanted in the patients with acute ankle injury, the Amsterdam Pediatric Wrist Rules has not gained much attention among orthopedic surgeons. The reason could be due to more fractured bones in wrist trauma compared with more ligamentous injuries in ankle injuries, which warrants X-ray evaluation in pediatric acute wrist trauma.⁵ On the other hand, it should be remembered that the Amsterdam Pediatric Wrist Rules is neither designed to replace the proper physical examination nor the clinical experience of the orthopedic surgeon.

2.2 The ALARA principle

There are now many ways to lower the exposure of children to ionizing radiation without sacrificing diagnostic reliability. The ALARA (as low as reasonably achievable) principle attempts to optimize radiation without reducing image quality. Limiting the time of radiation exposure, increasing the distance between patient and the radiation source, and suitable radiation shielding are the fundamental of the ALARA principle. Some technical regulations including pulsed radiation, removable scattered-radiation grid, and use of sighting device are essential for lowering radiation dose to the patient. Precise collimation, specific automated detectors, and accurate patient positioning are other strategies for decreasing the radiation level.⁶

The newer X-ray machines have the overhead tube and laser marking to adjust the field size, allowing better scattered radiation protection and automatic dosage fine-tuning. The wrist gives unique opportunity to keep the body out of radiation zone while resting the limb directly on the cassette. Additionally, newer storage plates could achieve excellent levels of detail and contrast with lower radiation dosages.

The AO foundation recommends to position the X-ray source under the table and the intensifier above to decrease the amount of scattered radiation by half. It is also recommended to place the patient as close as possible to the intensifier and further away from the X-ray tube to reduce scattered radiation. By doubling the distance from the x-ray tube, one fourth of the scattered radiation would be received.⁷

2.3 Shielding

There are some state-of-the-art strategies for those children who are selected for evaluation by X-ray. The anatomical location of the wrist gives a unique opportunity for the use of out-of-field contact shielding and patients radiation protection. Lightweight double-sided lead aprons, thyroid shields as well as leaded glasses are now available in pediatric sizes, which ensures better radiation protection while improving patient comfort.

Bismouth-coated shields are now commercially available for the protection of radiosensitive organs and have been used during CT scans successfully. These shields could absorb the lower energy spectra of the X-ray beam, reducing the patients’ dose, without decreasing the image quality. Appropriate bismouth-coated shields could be potentially applied over the injured extremity producing acceptable diagnostic images with less radiation exposure.⁸ On the other hand, orthopedic surgeons must learn to accept noisier not-optimal images that are nevertheless diagnostic because of risk reduction of repeated exposures.

2.4 Communication

Good communication with the child and parents is the next key strategy in achieving suitable diagnostic imaging. The child should be prepared before arrival in the X-ray department and his/her concerns appropriately addressed by the health professionals. The procedure could be briefly discussed with the child and parents highlighting that it is non-painful and non-invasive. Efforts should be made to support the child to join in the procedure by sharing his/her views and concerns.⁹

Although older children could have more cooperation during diagnostic radiology through communication, younger children might need immobilization by using various restraining and distraction devices. Accompanying parent could be so helpful during the procedure to get best results.

3.1 No reduction

In cases of pediatric non-angulated distal radius fractures, immobilization in a cast or splint for 3–4 weeks is all needed. No further in-cast radiographies to evaluate position of fractured fragments are needed. This category includes buckle, greenstick, growth plate fractures type I and V, and could also involve those children with suspected or occult distal radius fracture. This strategy limits the number of radiation exposures to just two shots taken during the diagnosis.

3.2 Reduction

In children with angulated distal radius fractures different intervention are applied including close reduction + casting, close reduction + pinning + casting, and open reduction + pinning + casting. This treatment strategies usually take place in the operating theater and include manipulation under the C-Arm magnification.

The same principles of limited time exposures, reduced radiation dose, suitable distancing, and shielding apply when working with the C-Arm magnification. Anatomic landmarks on wrist and laser targeting are so helpful for radiation dosage and collimation adjustment. It should be remembered that using the image intensifier as a table is a common mistake due to the scattered radiation.

Appropriate lead apron shielding during the reduction maneuver and pinning is mandatory. The thyroid, torso, and gonad shields could be placed accordingly without disturbing the operating field or C-Arm machine. The upper extremity could be outstretched easily to increase the distance between the body and the operating field.

There are some state-of-art techniques for orthopedic surgeons to reduce the radiation exposures. Although, there is no limit for reduction attempts, the confirmatory radiation exposure must only be done when the tactile reduction is confirmed. No oblique exposures or live fluoroscopy are needed for reduction confirmation. For those cases who need percutaneous pinning, radiation exposure would take place after the implantation of all desired pins. Surgeons should feel comfortable for acceptance of those cases with remaining minor saggital and coronal malposition due to remodeling potential at physis of distal radius, especially in little children.

It is a common practice among orthopedic surgeons to apply some pins in the fractured fragments and then remove those undesired pins after radiation exposure. This strategy could also decrease the amounts of shots.

Newer C-Arm machines have an integrated computer and printer to save and print desired exposures. These printed images could be used as an alternative for the postreduction formal radiographs. This strategy could save time, expense and radiation exposure to children.¹⁰

4.1 Immobilization without reduction

Children with occult, buckle, green-stick, and growth plate fractures type I and V do not need further radiographies at follow-up visits. The cast or splint is removed at the final follow-up office visit without any possible complication. Actually, the single visit treatment of these patients has been recommended because of its excellent clinical outcomes.¹¹

For those children with suspected growth plate fractures type V, the treatment strategy consists of watchful follow-up visits for remodeling or growth plate arrest and subsequent limb shortening or deformity.

4.2 Immobilization with reduction±pinning

The chance of loss of reduction in cast is a major concern for orthopedic surgeons who select this technique. The phenomenon put extreme stress on the orthopedic surgeon to order serial radiographies for detection of early redisplacement. Although the rate of redisplacement is reported to be 22–33 %, the rate of re-intervention is much lower:4.7–8%.¹² In other words, most serial radiographies are unnecessary. Orthopedic surgeons should pay special attention to those cases who have risk factors of redisplacement in cast and avoid unnecessary repeated radiographies.

The risk of loss of reduction is very low for children in the group of reduction and pinning.¹³ Overall, the redisplacement rate had been reported about 3.6 % and a few needed a secondary procedure. So serial radiographies at follow-up visits are not usually necessary, and a final radiography for union confirmation is all needed at the last visit. Further radiographies for growth plate arrest or joint deformity are not routinely required due to the remodeling potential of the distal radius physis.¹⁴

There is a concept of using dual-energy X-ray absorptiometry (DXA) images for follow-up visits of pediatric distal radius fractures. Lower effective radiation doses in line with the concept of ALARA are its major benefits beside its comparable images with plain radiographs when measuring angulation and translation.¹⁵