Important Risk factors for a Child Re-breaking their Forearm

related talks: child forearm fracture (both bone forearm fracture), child broken arm, collar bone fracture, greenstick fracture

We are discussing a recent article published in the Journal of Pediatric Orthopedics titled: "Factors Influencing the Refracture of Pediatric Forearms" (see full article). 

A broken forearm in a child is one of the most common injuries in all of orthopedics (see talk).  So its very important to know all the risks associated with this injury so doctors can provide the best care to these kids.  This article highlights some very useful findings about one of the complications of pediatric forearm fractures.  

The good news is that re-fractures are exceedingly uncommon.  Despite hundreds of these injuries over the course of a decade, only 34 re-broke (1.4%).  Additionally, all of the ones that re-broke healed without problem, and only 2 (7%) required surgery.  In summary, even though this is the most common complication of a pediatric forearm fracture, its extremely uncommon, and even for kids that are unlucky enough to have this happen, chances are that they will do great with another cast.   

The article identified to major risk factors for re-injury: 

1) persistent angulation (in kids, the bone can heal in a slightly bent position because it will continue to remodel as the kid growth and will end up straight after a year or two depending on the degree of bending).  The problem with allowing the bone to heal in a slightly bent position (over 10 degrees) is that it appears to put kids at increased risk for re-fracture because the bone is less biomechanically stable.  Bones that healed with at least 15 degrees of bending, re-fractured 40 days earlier than other re-fractures suggesting even less stability. 

2)  The location of the fracture was also important.  72% of re-fractures occurred in the middle 1/3 of the bone.  This area of bone has weaker blood supply than the ends of the bone and this is important because the blood supply is critical in delivering nutrients to allow the bone to heal.  Therefore, its likely that the bone is just healing slower, and less strong compared to other fracture sites at equivalent time points. 

References

1. Landin LA. Epidemiology of children's fractures. JPO 1986; 6: 656-660.  full article. Forearm fractures are the most common fx in kids. 

2. Fiala M, Carey TP. Pediatric forearm fractures: an analysis of refracture rate. Orthop Trans 1994; 18: 1265-66. this paper cites a 5% refracture rate (higher than the discussed paper).

3. Bould M, Bannister. GC. Refractures of the radius and ulna in children. Injury 1999; 30: 583-86. full article. cited mid-shaft fx as 8x risk of refracture.