Smith Fracture · What Is It, Difference from Colles, and More

A Smith fracture is a type of distal radius fracture that typically results from falling onto a flexed wrist with the palm facing downward. The position of the wrist causes the broken piece of the radius to shift toward the palm side of the hand, resulting in a volar displacement.  

Distal radius fractures are one of the most common fractures of the upper extremity, however, Smith fractures only account for around 5% of them. That is mainly because when someone falls, they instinctively extend their arms to protect themselves, resulting in a fall onto an outstretched hand (i.e., FOOSH). This results in the more common Colles’ fracture, where the displaced fragment shifts to the back of the hand. For a Smith fracture to occur, the person needs to fall onto a flexed wrist, which is much less common in accidental falls.   

There are three types of Smith fractures. Type I is the most common with a transverse break outside the wrist joint. Type II, also called a reverse Barton fracture, is an intra-articular fracture, or a fracture that occurs on the articular surface (i.e., joint surface) of the radial-ulnar joint. Lastly, a type III fracture is least common and involves a juxta-articular oblique fracture, or a fracture that occurs as a curved or angled break at the articular surface of the wrist joint. 

Smith fractures often appear as a deformity on the distal forearm; however, the direction of displacement may be difficult to assess without the use of radiographs. Classically, the deformity is described as “garden spade” or “reverse dinner fork” because when viewed laterally, the hand and wrist are slightly curved posteriorly. Typically, individuals with a Smith fracture may also present with swelling, pain, and decreased range of motion in the wrist.  

Less commonly, the neurovascular system in the wrist and hand may be compromised due to compression of one or more nerves from the fractured bone. If the neurovascular system is affected, the individual may experience symptoms such as tingling, numbness, or weakness in the specific areas of the wrist or the hand that is innervated by the affected nerve. When the median nerve is compressed, an individual may experience symptoms of acute carpal tunnel syndrome in the thumb, index, middle, and ring fingers. More rarely, an individual may have radial nerve compression, which may affect digits on the radial side of the hand, like the thumb or index finger. Ulnar nerve compression may also occur rarely, which affects digits on the ulnar side, like the pinky or ring fingers. A person may also experience acute compartment syndrome of the forearm, characterized by pain greater than expected and paresthesia, a tingling feeling sometimes described as “pins and needles.” 

Smith fractures can be challenging to treat and often require surgery to successfully restore the radial alignment. The most conservative approach to surgical treatment is performing a closed reduction, which occurs when the bone is put back in place without surgery and, instead, by longitudinal traction while the individual is under sedation or given general anesthesia. When the fracture is unable to be reduced and is unstable (i.e., the bones continue shifting or become displaced despite attempts to reposition and stabilize), open reduction internal fixation (ORIF) is often performed. During ORIF, a plate and screws are implanted to stabilize the bones. Unstable fractures in an individual with good bone quality may be also treated by a closed reduction with percutaneous pinning (CRPP), which involves placing pins or wires, often Kirschner wires (K-wires), through the skin to hold the reset bones in place until the fracture has healed. External fixators may be used to stabilize an individual with lots of trauma before transferring them or for open fractures. However, external fixation is rarely used as pins may loosen or become infected.  

Once reduction is complete, a cast or splint is usually placed in an extended position, where the wrist is flat, for about four to eight weeks. Follow-up radiographs are often performed to make sure bone alignment is maintained before allowing complete wrist movement. After cast removal, physical therapy and splinting is typically prescribed for six to eight weeks until movement is painless and strength is restored. Non-steroidal anti-inflammatories (NSAIDs) (e.g., ibuprofen, aspirin) or opioid analgesics (e.g., oxycodone, hydrocodone) may be prescribed to control pain during recovery. 

The prognosis of Smith fractures is generally good with proper treatment. The risk of complications is higher in complex fractures, such as those with intra-articular traces, and when treatment is delayed or there hasn’t been adequate bone reduction or fixation.  

One of the main complications is malunion, which happens when the bone heals in the wrong position, usually because the fracture wasn't properly aligned or stabilized during healing. A residual volar displacement is commonly referred to as a garden spade deformity since it has a similar curvature to a garden spade. A malunion may also lead to delayed carpal tunnel syndrome if the carpal tunnel becomes consistently narrowed. Malunion occurs more commonly in older adults with low bone density as they may have trouble maintaining the closed reduction.  

Many people also experience complex regional pain syndrome (CRPS), characterized by chronic pain in the hand and wrist often associated with sensory, motor, or vasomotor issues. When the wrist is splinted at an angle greater than 15 degrees, there is an increased risk of acute CRPS. That’s because this positioning places increased tension in the muscles of the wrist and forearm, disrupting circulation and nerve signaling. CRPS is typically treated by physical and occupational therapy. Any continuing neuropathic pain may be treated with NSAIDs and adjunctive agents like gabapentin. Despite appropriate treatment, many individuals have some prolonged disability. 

Less commonly, the extensor pollicis longus (EPL) may be entrapped or ruptured, resulting in an inability to extend the thumb. Typically, this occurs within seven weeks of the injury and is diagnosed after the EPL ruptures, at which point surgical treatment is necessary.