Premature Physeal Closure of an Extraphyseal Distal Radius Fracture Secondary to Smooth Kirschner Wire Fixation: A Case Report

Premature closure of the distal radius physis is rare and is usually associated with a fracture pattern that involves the physis. We present a case of an extraphyseal distal radius fracture treated with closed reduction and percutaneous smooth Kirschner wire fi xation that went on to premature physeal closure at the site of wire fi xation. Surgeons should be aware that closures of the distal radius physis after metaphyseal fractures can occur with use of smooth Kirschner wires and that patients should be followed closely. Case Report Premature Physeal Closure of an Extraphyseal Distal Radius Fracture Secondary to Smooth Kirschner Wire Fixation: A Case Report Michael C Doarn* and Mark S Cohen All work was done at Midwest Orthopaedics at Rush, 1611 W. Harrison Street, Suite 201, Chicago, IL 60612 Received: 22 September, 2017 Accepted: 27 January, 2018 Published: 29 January, 2018 *Corresponding author: Michael C Doarn, MD, TriState Specialists, LLP 2730 Pierce Street, Suite 300, Sioux City, IA 51104, Tel: 712-226-7110 Fax: 712-2771662; Email:


Introduction
Distal radius fractures are common in the pediatric population [1]. The majority are physeal Salter-Harris type I or II patterns [2]. Extraphyseal fractures often occur and usually go on to union without complications.
Pediatric fractures of the distal radius that involve the physis have a risk of premature physeal arrest. This has been reported in the literature between 1 and 7% [1]. Salter-Harris type II patterns are reported as having the highest risk for physeal closure [3]. Risk factors include multiple attempts at closed reduction and reduction performed greater than 7-10 days from the injury [1,3]. Metaphyseal distal radius fractures that are extraphyseal can be associated with premature physeal closure. However, this is extremely rare. All six such reported cases involved complete closure presumably due to a concomitant Salter-Harris type V compression injury to the growth plate [4].
We report a case of a patient with an isolated extraphyseal distal radius fracture that developed a partial premature physeal closure after smooth Kirschner wire fi xation was used.
The closure occurred directly where the pins had crossed the growth plate. This ultimately required a complex corrective osteotomy with lengthening of the radius.

Presentation of the Case Report
An 11 year-old right-hand-dominant healthy male presented after sustaining an isolated injury to his right wrist while snowboarding two days prior. The patient was seen at an outside emergency room and a splint was applied without manipulation. On examination, he had a normal neurovascular exam and full digital motion. An obvious clinical deformity was present. Radiographs of the right wrist revealed an extraarticular, extra-physeal distal radius fracture with dorsal angulationure 1). There were no irregularities seen within the s Three days after injury, consent was obtained, and the patient was taken to the operating room. There he underwent a manipulative closed reduction. Once reduction was obtained, percutaneous pin fi xation was utilized to stabilize the fracture.
Under fl ouroscopic guidance, two smooth 0.062 inch Kirschner wires were placed into the radial styloid tip and across the  Figure 8).

Discussion
Disruption of distal radius physeal growth can occur from various etiologies including infection, ischemic conditions, and repetitive stress. Disruption is usually secondary to wrist trauma [1][2][3][4][5]. Closure of the radial growth plate occurs most commonly after Salter fractures which involve the physis. Other than this pattern, there have been six reported cases of pediatric extraphyseal metaphyseal fractures that developed premature closure. These cases were all treated non-operatively. In each case, the entire radial physis closed prematurely. The growth plate disturbance in these cases was attributed to a presumed concomitant crush injury to the distal radial physis that was unrecognized [2,4,6]. This is the fi rst reported case that we are aware of involving a distal radius extraphyseal fracture treated across the physis have shown no signifi cant risk to physeal growth [7,8]. However, most studies have involved the distal femoral physis. In addition, the location of the wires (centrally versus peripherally) has not been shown to be signifi cant in animal models [8]. The exact cause of the bony bar from the pins in our case is thus not entirely clear. It is assuredly a rare complication.
Once physeal arrest occurs in the radius and affects wrist and forearm anatomy, including the distal radioulnar joint, various treatment options exist [9][10][11][12]. Patients can undergo a lengthening osteotomy of the radius, a shortening osteotomy of the ulna (typically with closure of the ulnar physis), or a combination of the two [1,10,11]. Due to the gross three dimensional deformity present in our patient with reversal of the normal radial inclination, we chose to realign the wrist and forearm by correcting the radius alone. While an additional shortening of the ulna could have been considered, we found this not to be necessary intra-operatively. In addition, we did close the remaining physis of the radius and that of the ulna.
With the signifi cant lengthening of the radius, a very large trapezoidal defect remained. We chose to fi ll this with non-structural bone graft, rather than a more traditional corticocancellous bone block. This was facilitated by the use of a locking plate, which maintained the three-dimensional anatomy of the reduction during healing.
In conclusion, we believe that adolescents with distal radius fractures that are treated with pin fi xation, regardless of whether the fracture involves the growth plate or not, should be followed with surveillance radiographs to document normal growth and alignment of the wrist for at least one year after surgery. In this way, early growth plate disturbances might be identifi ed before a signifi cant deformity occurs that might require a corrective radius osteotomy as seen in our patient.  with smooth Kirschner wire fi xation complicated by premature physeal closure. In our patient, the growth plate closed with a bony bar on the radial side, exactly where the initial pins were placed. We thus believe that a concomitant Salter fracture to the radius is highly unlikely as these usually have complete physeal closure. We can only conclude that the bony bar was secondary to our surgical intervention.
Previous studies evaluating the effect of smooth pins placed