Forearm Injuries

The forearm is the portion of the body between the elbow and wrist joints.  Unfortunately, they are one of the most commonly broken bones - they can break when either children land directly on their forearm or when they reach their hand out to break a fall.

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FOREARM ANATOMY

The forearm is made up of two bones - the radius and the ulna.  The main function of the forearm is rotation - that is -  It allows us to turn our wrist up and down.  The forearm needs to rotate our wrists down for activities such as typing and texting, and it needs to rotate our wrists facing up for such tasks as carrying a heavy box.  In order for the forearm to rotate correctly, the bones need to be straight enough so that the radius bone can rotate over the ulna bone. 

There are growth areas at the top and bottom ends of the forearm.  The growth areas on the bottom closer to the wrist are the ones that provide more growth to the forearm, and at the same time, the ones more vulnerable to injury.  Note in the picture that the growth area (known as the physis) is black while the rest of the bone is white.  Since bone has calcium, it projects as white on the xray.  On the contrary, the growth area is made of cartilage, and it has no calcium, so therefore it is not visible on xray and shows up as black.  

FOREARM FRACTURES: 

Forearm fractures are quite common in children of all ages, and are typically the result of a fall. Fractures that occur in children less than ten years old often heal well without surgery and are treated in a cast for approximately six weeks.

However, sometimes, the fractures move within the cast into an alignment that may decrease function in the future. If that is the case, your doctor may recommend a surgery to place a temporary rod in either one or both of the bones in the forearm. The rods typically stay inside the bone for approximately three to six months and are then removed surgically on an outpatient basis.

Initially, all attempts are made to treat a preteen's or adolescent's fracture with a cast as well. But often, preteen and adolescent forearm fractures may require more than cast treatment for the following reasons:

  1. These children are older and do not have as much growth remaining. Therefore, the bones have to heal straighter in order to ensure proper forearm functioning in the future.
     
  2. The properties of a preteen or adolescents bone differ from a child's in that the lining around the older bone is not as thick. This makes it easier for the broken bone to move around in the cast which is not conducive to proper healing.
     
  3. Older children also have bigger and stronger muscles than younger ones. These muscles are more likely to cause the fracture pieces to move around in the cast, which is again not conducive to proper healing.
     

Once the fracture is healed enough to be removed from the cast, sometimes your physician or PA may recommend a fracture brace to wear for a few weeks. Unfortunately, the fractures that occur in the middle of the forearm have a high chance (approximately 5%) of breaking again within the first eighteen months after the initial break. Therefore, it is important to keep the forearm protected for as long as possible.

MONTEGGIA FRACTURES

A Monteggia fracture is when there is a fracture in the ulna bone close to the elbow joint along with a dislocation of the radiocapitellar joint.  Sometimes, the ulna bone is bent rather than broken and it can be difficult to recognize the injury.  The most important part of treatment is to a) recognize the fracture, and b) ensure that the radiocapitellar joint is back in its normal alignment.    In order to recognize the injury, your phyician needs to understand the fracture pattern.  It is also extremely important that when you're child is in the ER, that the entire forearm is x-rayed.  For example, when looking at the radiograph on the left, note that the forearm fracture was not seen on the initial xray, and it was only recognized when the forearm was x-rayed as well (see below).

In adults, all Monteggia fractures are treated surgically.  In children, however, that is not always the case.  The orthopaedic surgery resident (at night) or nurse practitioner (Stephanie de Jager) may attempt to maniputlate the fracture back into a normal position under heavy sedation in the emergency room.  If the joint is able to get back in place, then your child will be placed in a cast above the elbow.  However, if the joint cannot be put back into position, then surgery will likely be recommended.  

Surgery typically involves placing some type of rod down the ulna bone to make it straight.  Once the ulna bone is straight, the radiocapitellar joint typically goes back into its normal alignment.  The rods typically are removed in 3-6 months as they become too prominent near the elbow joint.

In the radiographs below, notice on the left this is the forearm xray of the same patient that is shown here on the left.  Notice that now one can see the broken ulna bone.  In this particular child, the ulna bone had penetrated through the skin (therefore, known as an open fracture), and this child was treated in the operating room not only to straighten the ulna bone with a rod, but also to surgically clean the bone and protect against the risk of infection.  The other radiograph was taken 3 months after the injury, demonstrating how nicely the fracture healed, and that the joint remains in place.  This young girl had the rod removed 4 months after the injury and had a 100% recovery.

DISTAL RADIUS FRACTURES 

Distal radius fractures are extremely common in children. The break occurs at the bottom end of the bone typically where it is most wide (in the metaphysis), or at the growth area (physis).   Many of these fractures can be treated in a cast for 3-4 weeks, others are manipulated ("reduced") in the emergency room and then placed in a cast, and lastly, for the most severe ones, are surgically treated.  Discussed below are two special types of distal radius fractures.

Distal Radius Buckle Fractures:

Buckle fractures are extremely common in children- they do not involve the growth area of the bone.  The bone "bends" or buckles, rather than completely breaking.  These fractures are typically not as painful as a true break when the bones completely separate.  It is not uncommon for children to present to COA 3-4 days after the injury as they continue to have pain that is not getting better.  They are typically treated in a short cast for three weeks.  After that, your COA provider may or may not recommend a brace for a limited period of time.  There should not be any significant long term problems from these types of fractures.  

Distal Radius Physis Fractures:

Fractures of the growth are of the distal radius are also very common, and typically occur in an older age group than those with buckle fractures, essentially due to the different mechanical properties of the bone over time.  These fractures are treated differently than other types of fractures, namely because of the risk of future growth probelms.  Risk of growth problems typically depends upon the severity of the initial injury.  

Distaradius physeal fractures heal relatively quickly.  Most children are in a cast up to 6 weeks.  Oftern times, a long cast is applied first, and this is to prevent the forearm from rotating.  Once the facture has undergone its iniitial healing (somewhere between 2-4 weeks), then your child will be converted into a cast below his elbow for the duration of treatment.  Depending on the severity of the fracture, it would not be uncommon for your child to return 6-9 months later to evaluate whether or not the bone was able to grow aftter injury.  If your child has a break through the growth area, and the bones are very displaced (separated away from each other), it would be typical for a member of the COA team to attempt to realign the fracture with heavy sedation.  CAution is taken, however, not to perform too many manipulations.  Excessive attempts may damage the growth area too much.  In addition, once the fracture begins its initial stage of healing (typically after the first week), then no attempts are made to manipulate the fracture.  In that circumstance, the risk of growth problems from moving the fracture is worse than leaving it alone.  Often times, the bone has excellent remodeling potential - meaning it is able to straighten itself out over time.  Note in the xrays below the break through the growth area.  This child presented one week after injury.  He had no manipulation performed in his local ER.  His clinician recommended to "leave the bone alone" to allow it to remodel.  Note in as little as three months how quickly the bone corrected itself.