Smith Fracture: Symptoms, Types, Causes and Treatment

Smith’s fracture is a distinctive wrist injury that requires careful diagnosis and management. Sometimes called the “reverse Colles’ fracture,” it involves a break at the distal radius with the fractured fragment displaced toward the palm (volar displacement). Although less common than other wrist fractures, missing or mismanaging a Smith’s fracture can lead to significant and lasting disability. In this article, we’ll explore Smith fracture’s symptoms, its classification, causes, and the latest evidence-based treatment options.

Symptoms of Smith Fracture

When a Smith fracture occurs, the signs can be subtle or dramatic. Correctly recognizing these symptoms is crucial for timely diagnosis and proper management—a missed Smith fracture may lead to worse outcomes and permanent limitations 5. Let’s summarize the hallmark features and complications seen in Smith’s fracture.

Symptom	Description	Complications	Source(s)
Wrist pain	Acute pain at wrist, worse with movement	Persistent disability	5
Swelling	Noticeable around wrist and hand	Limited range of motion	5
Deformity	“Garden spade” (palmar angulation)	Misdiagnosis as Colles’	5
Extensor tendon issues	Entrapment, rupture, or dysfunction	Thumb/finger movement loss	6 7 8
Reduced grip	Weakness or inability to grasp	Functional impairment	5

Table 1: Key Symptoms

Recognizing the Clinical Presentation

Smith fractures typically present with pain and swelling centered over the distal radius, just above the wrist joint. The wrist may look deformed, often described as a “garden spade” appearance because the hand is displaced toward the palm, the opposite of the classic Colles’ fracture 5. Patients often report difficulty moving the wrist or fingers due to pain and swelling.

Neurological and Tendon Involvement

A crucial aspect of Smith’s fracture is the risk of tendon entrapment or rupture. The injury can trap or tear the extensor tendons—especially the extensor indicis proprius, extensor digitorum communis, and extensor pollicis longus—leading to dysfunction of the thumb or fingers 6 7 8. This can manifest as:

• Inability to extend the thumb or index finger
• Pain or a “snapping” sensation with movement
• Loss of grip strength

In cases where tendons are caught in the fracture site, closed reduction may be impossible, and open surgery may be required to restore function 7 8.

Long-term Consequences

Even with adequate treatment, a degree of residual disability—such as reduced range of motion or persistent pain—may persist. However, these outcomes are significantly less severe than in cases where diagnosis is delayed or the fracture is mistaken for a Colles’ fracture and treated incorrectly 5.

Types of Smith Fracture

Smith’s fracture is not a one-size-fits-all injury; it can be classified into several types based on fracture patterns and patient demographics. Recognizing the type helps guide treatment and predict outcomes.

Type	Description	Patient Group	Source(s)
Type I	Extra-articular, transverse distal radius	Younger adults	1 2 3 5
Type II	Intra-articular, oblique fracture	Adults/elderly	1 2 3 5
Type III	Juxta-articular, involving joint surface	Elderly, complex	1 2 3 5
Type IV	Pediatric/variant, specific demographics	Children	5

Table 2: Smith Fracture Types

Classification Systems

The most widely referenced system categorizes Smith’s fractures into three (sometimes four) types, primarily based on X-ray appearance and age 1 2 3 5. Here’s a breakdown:

Type I (Extra-articular)

• The most common type, usually seen as a simple transverse fracture of the distal radius, with the fragment displaced toward the palm.
• Typically occurs in younger adults from high-energy trauma 1 2 3 5.

Type II (Intra-articular, Oblique)

• The fracture line extends into the wrist joint, making the break more unstable.
• More commonly seen in older adults or after a complex injury 1 2 3 5.

Type III (Juxta-articular)

• This type involves the articular surface but is closer to the joint, often with a more comminuted (shattered) pattern.
• It is more frequent in elderly patients and those with osteoporotic bone 1 2 3 5.

Type IV (Pediatric/Variant)

• Some sources mention a fourth type, typically seen in children, with unique fracture characteristics 5.

Importance of Accurate Typing

Correctly identifying the type of Smith fracture is essential, as it directly influences the choice between conservative and operative treatment. The stability and complexity of the fracture, as well as patient age, play a key role in planning management 2 3.

Causes of Smith Fracture

Understanding what causes a Smith fracture helps in both prevention and education. Contrary to popular belief, the mechanism often differs from that of the more common Colles’ fracture.

Cause	Mechanism	Frequency	Source(s)
Fall on palm	Hand in pronation, impact on palm	61% of cases	4
Direct trauma	Blow to dorsum of wrist	Less common	4 1
Pronation injury	Twisting motion during fall	Frequent cause	1
Unknown	Unclear mechanism	~23% (uncertain)	4

Table 3: Causes of Smith Fracture

The Typical Injury Mechanism

A Smith fracture most commonly results from a fall onto the palm of the hand, with the wrist in a flexed (palmar) position and the forearm in pronation (rotated inward) 1 4. This is in contrast to a Colles’ fracture, which typically occurs with the wrist extended.

Evidence from Clinical and Experimental Studies

A clinical survey and biomechanical modeling have shown that Smith’s fractures occur when the angle between the forearm and the ground is about 30°–45° in the sagittal plane and 75°–90° in the coronal plane. In cadaveric experiments, such impact led to Smith’s fractures in the majority of cases, confirming that falling on the palm with the wrist flexed is the primary cause 4.

Less Common Mechanisms

• Direct Trauma: A direct blow to the back (dorsum) of the wrist can also result in a Smith fracture but is less frequent 1 4.
• Twisting Injuries: Pronation with forceful twisting during a fall may contribute to the injury pattern 1.
• Other: Rare causes include falls on a fisted hand or complex combination injuries 4.

Demographic Notes

Smith fractures can affect adults of any age but are more common in middle-aged and elderly individuals, particularly women, due to osteoporosis 4 5.

Treatment of Smith Fracture

Managing a Smith fracture requires a nuanced approach. The treatment selected depends on the fracture type, patient factors, and potential complications. Here’s a comprehensive overview of evidence-based options.

Treatment	Indication/Type	Key Details	Source(s)
Closed reduction	Type I, some II; stable fractures	Supination, above-elbow cast, 6 weeks	1 2 5
Internal fixation	Unstable Type I, Type II	Ellis plate or palmar T-plate	2 3 9 10
K-wires & cast	Simple articular, large palmar frag	Less invasive, selected cases	10
Bone grafting	Comminuted or osteoporotic fractures	Augments fixation	10
Tendon surgery	Entrapment/rupture of tendons	Tenolysis, repair for lost function	6 7 8

Table 4: Treatment Approaches

Initial Management: Closed Reduction and Immobilization

For most extra-articular (Type I) and some stable intra-articular (Type II) Smith fractures, closed reduction is the first-line treatment 1 2 5. The technique involves:

• Reduction by Supination: The wrist is manipulated into maximum supination (rotated outward) to counteract the typical pronation injury mechanism 1 5.
• Above-Elbow Plaster Cast: Immobilization in a cast that extends above the elbow is recommended for six weeks to maintain alignment and prevent redisplacement 5.

Indications for Conservative Treatment

• Minimally displaced fractures
• Extra-articular (Type I) fractures
• Good alignment after closed reduction

Operative Treatment: Internal Fixation

Surgical intervention is indicated for:

• Unstable or irreducible fractures
• Persistent palmar angulation despite casting
• Intra-articular (Type II) fractures
• Comminuted or complex juxta-articular (Type III) fractures 2 3 9 10

Fixation Options

• Ellis Plate: A specialized plate fixed to the lower anterior aspect of the radius, suitable for Type II fractures and unstable Type I 2 9.
• Palmar T-Plate: Especially favored for intra-articular fractures, offering stable anatomical reconstruction 10.
• K-wires and External Fixators: Used in selected simple articular fractures with large palmar fragments or when plating is not feasible 10.
• Bone Grafting: Provides additional support in cases with significant bone loss or osteoporosis 10.

Outcomes

Operative treatments generally yield good to excellent functional results across all fracture types, with anatomical reconstruction correlating with the best outcomes 3 10.

Special Considerations: Tendon Involvement

Entrapment or rupture of extensor tendons (notably the extensor pollicis longus) is a notable complication that can prevent successful reduction and cause lasting disability 6 7 8. In such cases:

• Open Surgical Release (Tenolysis): Required to free or repair the trapped tendon.
• Dorsal Surgical Approach: Sometimes necessary for visualization and correction 7 8.

Timely identification and management of these complications are crucial for restoring full hand function.

Duration and Monitoring

Regardless of treatment strategy, regular follow-up and imaging are essential to ensure maintenance of reduction, healing progress, and early identification of complications 5.

Conclusion

Smith’s fracture is a unique and potentially complex injury of the wrist. Early recognition, precise classification, and tailored management are essential for optimal recovery. Here’s a summary of the key points:

• Symptoms: Smith fractures present with wrist pain, swelling, palmar angulation, and risk of tendon entrapment or rupture 5 6 7 8.
• Types: There are three main types (extra-articular, intra-articular, and juxta-articular), sometimes with a pediatric variant, each with specific management implications 1 2 3 5.
• Causes: Most commonly results from a fall onto the palm with the wrist flexed and forearm pronated, differing from the mechanism of Colles’ fracture 1 4.
• Treatment: Includes closed reduction and casting for stable fractures, and surgical fixation for unstable or complex types. Complications like tendon involvement may require open surgery 1 2 3 5 6 7 8 9 10.

By staying alert to the distinctive features of Smith’s fracture and choosing evidence-based interventions, clinicians can significantly reduce the risk of long-term disability for their patients.