Distal radius fractures are simple and complex at the same time. Here are the practical things you need to know as a medical student (there’s more than this, but this is a good start):
- How do radial fractures classically present?
- How do you read the xrays?
- How do you reduce the fracture, and what is the splinting technique?
- When will the fracture need surgery, and when will it need nonoperative therapy?
If you want to know what types of questions to ask patients when seeing them for orthopedic conditions go to this post:
70 year old woman with a history of osteoporosis presents to the emergency department with 10/10 pain to her right wrist that began immediately after a ground level fall. She also notes deformity of the right wrist.
- Skin intact (Always need to comment on whether a fracture is open or not)
- Deformity of wrist with swelling
- SILT (Sensation intact to light touch) radial, median, ulnar nerves
- Motor intact to AIN, PIN, Ulnar nerves
- Radial pulse 2+, Capillary refill <2 seconds
The presence of any paresthesia or numbness in the median distribution warrants careful attention because acute carpal tunnel syndrome has been reported in 5.4% to 8.6% of all distal radius fractures (Levin, JAAOS)
AP and Lateral Xrays of the right wrist are ordered and show the following:
(It is common to get a 3-view set of wrist xrays, oblique view is missing here):
Diagnosis: – dorsally displaced distal radius fracture.
(90% of distal radius fractures have this pattern!)
*Pro Tip*: Always consider the distal and proximal joint. Examine the elbow, obtain radiographics of the forearm and elbow if there is pain or concern in a high energy injury.
Reading the X-ray
As a medical student, you should try to keep the interpretation of xrays simple. Here is a sample interpretation of the above xrays:
“This is a 2 view, AP and lateral, of the right wrist of a skeletally mature individual demonstrating a posteriorly displaced distal radius fracture.”
For more details go to: System for reading wrist xrays
Here is the list of normal values for the distal radius, that can be helpful to guide your reduction and understanding of what normal usually looks like. It can be frustrating because there is a lot of anatomic variation. Ideally you line up the cortices and get it back to looking how it did before the fracture.
- Radial inclination should be around 24 degrees (range 21-25 degrees)
- Radial height should be around 12 mm (range 10 – 17mm)
- Volar tilt should be around 12 degrees (range 2-20 degrees)
*Pro Tip:* A mnemonic that can be used to remember this is 12+12 = 24*
What do you do next?
Regardless of what future surgical management the patient may have (if it all), you should perform a reduction in the ED in order to provide pain relief, reduce swelling, and alleviate potential compression of the median nerve (which could cause carpal tunnel syndrome).
This is accomplished first with IV sedation or via hematoma block. After appropriate sedation, reduction is next.
This can be achieved with either ketamine or propofol. To note, propofol is generally used for everyone except children and patients with low blood pressure.
The main problem with propofol is its side effect of decreasing blood pressure and patients going apneic. If patients stop breathing on propofol that means their muscles are perfectly relaxed for you to be able to reduce to your heart’s content. Oftentimes ED doctors will be slow to give patients enough propofol for you to effectively perform the reduction, so it can be a struggle to get enough sedation (this is often a problem with hip reductions because there is much more muscle mass in the hip than the distal radius).
Ketamine, on the other hand, can dissociate patients without decreasing blood pressure. So in trauma situations some doctors will do ketamine or ketamine and propofol (sometimes they will ask you what you want depending on your institution).
You may also opt for a hematoma block instead of sedation, especially in the elderly as they typically do well with hematoma blocks. Subacute fractures (>1-2 days old) do not do well with hematoma blocks because blood at fracture site is clotted. If there are any snags with getting someone a hematoma block such as local anesthetic allergies, extremely anxious, uncooperative, just jump to a sedation.
Here is the general flow and equipment involved in a hematoma block:
Equipment: Nonsterile gloves, iodine, 18gauge needle, ~10ml of lidocaine with or without epi, or you can do 5ml of lidocaine +5ml of bupivacaine (longer duration and helpful if you have to redo a reduction).
- Draw up lidocaine.
- Identify fracture site on the dorsal aspect of the injury and your start site
- Clean with antiseptic.
- Insert needle into fracture site.
- When you think you are in the spot you can pull back on the syringe and see if you get blood (from the hematoma). If you can, you are likely in the right spot.
- You can also use fluoro to check you are in the right spot. Lateral views are helpful for this (fluoro is helpful if you have to do a second block after a reduction attempt because it closes down the space to get to the fracture site).
- The picture below shows the person going in at a pretty steep angle, it can be helpful starting more proximal like the red arrow shows to be able to get under the fracture fragment.
- You center your needle on the radius diameter so the local anesthetic can reach the whole surface of the fractured bone.
- If your distal radius fracture involves the wrist joint and doesn’t have a great access point for your needle to hematoma block, you can put the local anesthetic in the wrist joint itself
- There is a soft spot on the dorsal wrist just ulnar and slightly distal to Lister’s tubercle where you can enter the joint to either inject local or pull wrist joint fluid for analysis (like in the case of septic wrist).
Here is where the soft spot would be.
Credit: Emergency Orthopedics Handbook
- Inject anesthetic.
- Wait 5-7min for block to set in
- Attempt Reduction
There are two methods of reduction: Finger trap (passive traction with arm in vertical position) and manual manipulation (elbow flexed to 90 degrees, apply longitudinal traction, hyperextend wrist to recreate mechanism and then volar translation). Studies have shown there is no superior method, including no significant difference in failure rates or acceptable alignment rates after 1 and 5 weeks (https://www.ncbi.nlm.nih.gov/pubmed/11886903). However, manual reduction is typically used as it is a faster procedure. Some institutions will use a finger-trap before reduction to fatigue the deforming muscular forces surrounding the wrists
- Distal radius fracture reduction technique:
- Place your thumb over the fracture site as a lever
- Hyperextend fracture fragment to dissociate it from the radial metaphysis to “recreate the fracture”, which is essentially bending the distal fragment more dorsally
- Apply longitudinal traction while keeping this recreation angle
- Lever the fracture fragment volarly into anatomic position
- Repeat neurovascular examination to assess motor, pulses, and sensation
- In the reduction maneuver, a common mistake is that people don’t recreate the fracture (bending the bone in the direction it was broken), and when you do that you want to keep the bone bent or in recreation angle while pulling longitudinal traction until you get it out to length and then you lever it over into alignment. People commonly recreate, pull traction and lose their recreation angle too early.
- If the fracture is a physeal fracture in a pediatric patient, you don’t want to manipulate too much (because you can cause physeal arrest) and physeal fractures should slide back in place, so you should not need as much recreation and traction This will be discussed further in future posts.
- Also, be careful in elderly patients with fragile skin to prevent skin tearing. This can be prevented by placing a piece of cotton cast padding between the patient’s skin and physician’s fingers during the reduction. Gloves are also more likely to tear skin.
- Splinting a distal radius fracture involves the use of a sugar tong plaster splint
- For positioning, you want their shoulders close to the edge of the bed on their fractured side, so that you can drop their arm down without bending the elbow, keeping at 90 degrees. Wrist should be in a neutral position.
- Lay out the cotton padding ahead of time so you don’t spend forever wrapping the arm. Lay out 4 layers for the skin side on the countertop, then you dip plaster and lay it on the 4 layers of cotton, then 1 layer of cotton over top, then you can position the plaster/cotton on the arm and wrap it into place with the Ace wrap.
- The plaster should start at the palm side just proximal to the MCPs, wrap around and then go to the dorsal side of the MCPs, if there is excess it is okay to fold back on the dorsal end. It is better to measure long than too short. If it is too short, you have to remake the splint.
- Start at the elbow with the ACE wrap then go proximal, covering the plaster/cotton webril
*Pro Tip*: Avoid positions of extreme flexion and ulnar deviation (Cotton-Loder Position) due to risk of precipitating carpal tunnel syndrome.
Confirming Appropriate Reduction
Always get a new set of xrays after your reduction. Evaluating key anatomical landmarks will help determine if the reduction is set appropriately. Again, normal is defined as:
- Radial inclination should be around 24 degrees (normal range 21-25 degrees)
- Radial height should be around 12 mm (normal range 10 – 17mm)
- Volar tilt should be around 12 degrees (normal range 2-20 degrees)
- To determine if parameters are acceptable after reduction to promote proper healing, evaluate the following:
- Radial inclination should be within 5 degrees of normal
- Radial height should be within 2-3mm of contralateral wrist
- Intra-articular step off should be less than 2mm
Note: this is the book answer, not always the practical one, we do NOT commonly get xrays of the contralateral side for reference.
Overall, you are shooting for getting the cortices lined up as perfectly as you can (even though it is debatable whether it will truly affect long term functional outcomes).
Above is an example of a reduction that was inadequate, there is a loss of volar tilt of the distal radius as well as length, and you can see that the posterior cortex of the distal radius is not lined up.
The hematoma block was reperformed under fluoro and this fracture was reduced and splinted correctly the second time. Do you see the posterior cortex of the distal radius and how it is lined up?
Here are the two reductions side by side so you can compare.
Some fractures will become displaced again after closed reduction. There are two factors that dictate the likelihood of this happening: age of the patient and initial degree of displacement. Other factors, known as the LaFontaine predictors of instability, include:
- dorsal angulation > 20 degrees
- initial radial shortening >5mm
- associated ulnar fracture
- dorsal comminution >50%
- palmar comminution
- intraarticular comminution
Of these factors, radial shortening, followed by dorsal comminution, are the most predictive of instability. If your reduction needs to be repeated due to instability, there is a < 50% satisfactory result (Orthobullets).
When would you take the patient to the OR?
There are many indications for surgery and several operative techniques. Indications include (Commit these to memory):
- Open fractures
- Associated neurovascular or tendon injury
- Associated fracture of the carpal bones
- High-impact injury
- Radiographic findings indicating instability (see factors above)
- Volar or dorsal comminution
- Displaced intra-articular fractures >2mm
- Radial shortening >5mm
- Associated ulnar fracture (not ulnar styloid)
- Severe osteoporosis (often depends on displacement)
- Articular margin fractures (dorsal and volar Barton’s fractures)
- Comminuted and displaced extra-articular fractures (Smith’s fractures)
- Die-punch fractures
- Progressive loss of volar tilt and radial length following closed reduction and casting
Operative techniques include percutaneous pinning, external fixation, open reduction and plate fixation, adjunctive fixation, and intramedullary fixation. Most commonly seen is volar plating, which we will discuss in future posts.
Please post your questions below!
https://www.ncbi.nlm.nih.gov/pubmed/28199291 (JAAOS, Distal radius fractures in the elderly)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4626227/ (Study on determining instability of distal radius fractures)
https://link.springer.com/chapter/10.1007/978-3-030-00707-2_8 (Lister’s tubercle picture)